BritishV8 Forum

I'm trying to find out the correct timing for my MGB V8 .... Its an original factory V8 with a Rover SD1 3.5L - which if I can believe the data available dates from 1979-1980 - Serial no. 11A32164. I have an Edelbrock 500 with a Mallory Unalite dist.

I had assumed that the dynamic iginition timing for these engines should be 10 BTDC at 1000rpm with the vacuum disconnected. I have seen other data that suggests either 6, 8, 12 BTDC and even a data sheet that suggests 2 ATDC for a 1979-1980 engine......Can anyone advise ?

Welcome to the message board, Conor!


Are you familiar with this index? http://www.britishv8.org/MG-factory-MGB-GT-V8-model.htm

Obviously, there's a lot that's not "original" about your engine installation, so you may need to modify the tuning for best results... but if you want to start from the tuning MG recommended...


British Leyland published this: http://www.britishv8.org/Articles/MGBGTV8-Technical-Notes.htm

Here's an excerpt:

Distributor      
Make/type      Lucas 35 D8
Serial number      41394
Rotation of rotor      Anti-clockwise
Dwell angle      26 to 28 degrees
Contact breaker gap      0.014 to 0.016 in. (0,35 to 0,40 mm)
Condenser capacity      0.18 to 0.24 microfarad

Centrifugal advance (decelerating with vacuum pipe disconnected)      
      33 to 37 degrees at 4900 rev/min
      28 to 32 degrees at 3600 rev/min
      24 to 28 degrees at 2600 rev/min
      19 to 23 degrees at 2000 rev/min
      14 to 18 degrees at 1600 rev/min
      9 to 13 degrees at 1200 rev/min

No advance below      600 rev/min
Vacuum advance      16 degrees
Vacuum advance - starts      5 in. (127 mm) Hg.
Vacuum advance - finishes      17 in. (432 mm) Hg.
Stroboscopic timing      8 degrees BTDC at 1000 rev/min


BritishV8 magazine has published several articles that describe other timing methodologies. I think this is probably a good one to start with: http://www.britishv8.org/Articles/Ignition-Tuning-201.htm

Alternatively, some people just a vacuum gauge to get timing into the right ballpark, as described here: http://www.britishv8.org/Articles/MGB-V6-Engine-Conversions.htm

Thanks Curtis.....I'll review the info with much interest !